Metal pigment composition package

Abstract

To provide a novel package for a metal pigment composition.SOLUTION: This package is for packing a metal pigment composition containing metal particles and composite particles having one or more coating layers on the surface thereof in a packing container, and satisfies the following conditions (1)-(4): (1) the composite particles are scaly in shape; (2) a volume reference D50 of the composite particles when a particle size distribution is measured by a laser diffraction type particle distribution meter is 1-30 μm; (3) moisture included in the metal pigment composition in the package is 0-1000 ppm with respect to the mass of the metal pigment composition; and (4) the packing container is made of a thin chromium-plated steel plate. At least one of the coating layers of the composite particles can be a silicon compound contained layer, and the metal particles can be aluminum or an aluminum alloy.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a package of a metallic pigment composition containing novel composite particles, and to a method for storing and transporting the package. More specifically, the present invention relates to a package of a metallic pigment composition containing novel composite particles that have little tendency to aggregate and can maintain excellent hiding power, color tone, etc. even after long-term storage, and to a method for storing and transporting the package. [Background technology]

[0002] BACKGROUND ART Metallic pigments have been used for metallic paints, printing inks, plastic blends, etc. for the purpose of achieving a cosmetic effect that emphasizes a metallic appearance. In recent years, the paint industry has seen a growing need to switch to water-based paints, which use fewer organic solvents, as a means of resource conservation and pollution prevention. However, there are still not enough practical water-based paints for metallic paints containing metal pigments. One reason for this is that metal pigments are prone to corrosion in water-based paints. When metal powders are present in water-based paints, corrosion occurs in either acidic, neutral, or basic conditions, or in multiple ranges, depending on the properties of the metals, resulting in the generation of hydrogen gas. This poses a significant safety issue in the paint and ink manufacturing processes of paint and ink manufacturers, as well as in the painting and printing processes of automobile, home appliance, and printing manufacturers. Furthermore, corrosion can cause the metal surface to lose its smoothness, pigment particles to aggregate, or pigment particles to deform, resulting in unavoidable color deterioration.

[0003] Patent Document 1 (JP 2003-147226 A) discloses an aluminum pigment having an inorganic molybdenum coating and a coating made of amorphous silica that covers the coating. Patent Document 2 (WO 2004 / 096921 A) discloses an aluminum pigment having an inorganic molybdenum coating and a coating made of amorphous silica that covers the coating and / or a coating formed from a silane coupling agent. However, all of the methods described in these patent documents inevitably cause changes in the color tone of the metallic pigment, and these methods also have the problem of causing aggregation and color tone changes of the metallic pigment, particularly during long-term storage in a package or during transportation in an uncontrolled environment.

[0004] Patent Document 3 (International Publication No. 2018 / 180936) discloses a coated pigment of composite particles that includes metal particles and a coating layer that is a silicon-containing compound layer, and has a small proportion of aggregates in which four or more particles are adhered to each other, with the aim of providing a coated pigment (metal pigment composition) that is dispersed with relatively few aggregates. However, Patent Document 3 does not provide any specific teaching on how to obtain the desired coated pigment with few aggregates, other than that it is preferable to adjust the stirring Reynolds number within a certain range. Furthermore, even if the ranges of characteristic parameters specified in Patent Document 3 are met, it is difficult to obtain sufficiently satisfactory hydrogen gas generation suppression performance, low aggregation, hiding power, and color tone. Furthermore, even with this coated pigment, it is not possible to solve the problems of aggregation and color change that occur during long-term storage in a package or during transportation in an uncontrolled environment. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-147226 [Patent Document 2] International Publication No. 2004 / 096921 Pamphlet [Patent Document 3] International Publication No. 2018 / 180936 Brochure Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a package of a metal pigment composition containing novel composite particles that has not been found in the prior art, as well as a method for storing and transporting the package. A further object of the present invention is to provide a novel technology which overcomes the disadvantages of the prior art, i.e., which provides excellent storage stability, little aggregation of individual particles, excellent hiding power, color tone, etc., and which can maintain these characteristics even during long-term storage in a package or during transportation in an uncontrolled environment. [Means for solving the problem]

[0007] As a result of extensive research to solve the above-mentioned problems, the inventors discovered that in a package in which a metal pigment composition containing composite particles having metal particles and one or more coating layers on the surface thereof is packed in a packaging container, by setting the moisture content of the metal pigment composition in the package within a specific range and using a packaging container on which a specific plating is formed, it is possible to suppress the progression of aggregation and color change of the metal pigment composition in the package, and thus completed the present invention.

[0008] That is, the various aspects of the present invention are as follows. [1]. A package in which a metal pigment composition containing metal particles and composite particles having one or more coating layers on the surfaces thereof is packed in a packaging container, the package satisfying the following (1) to (4): (1) The shape of the composite particles is scale-like; (2) Composite particles are those with a volume-based D when particle size distribution is measured using a laser diffraction particle size distribution analyzer. 50 is 1 to 30 μm, (3) The moisture content of the metallic pigment composition in the package is 0 to 1000 ppm relative to the mass of the metallic pigment composition; and (4) The packaging container is made of thin chrome-plated steel sheet. [2] The packaging body described in [1] above, wherein at least one of the coating layers is a silicon compound-containing layer. [3]. The package described in [1] or [2] above, wherein the metal particles are aluminum or an aluminum alloy. [4] The package according to any one of [1] to [3] above, wherein the metal pigment composition has a pH in the range of 5 to 9. [5] The package described in any one of [1] to [5] above, wherein when the sealed package is stored in an indoor warehouse at 20°C for one year, the residue of the metal pigment composition after storage is 0.1% by weight or less. [6] The package described in any one of [1] to [5] above, wherein when the sealed package is stored in a heated room at 60°C for three months, the residue of the metal pigment composition after storage is 0.1% by weight or less. [7] A storage method for storing a metal pigment composition at 0 to 50°C using the packaging described in any one of [1] to [6] above. [8] A method for transporting a metal pigment composition at 0 to 50°C using the package described in any one of [1] to [6] above. [Effects of the Invention]

[0009] According to the present invention, even when a metal pigment composition containing metal particles in a package and composite particles having one or more coating layers on the surface of the metal particles is stored and / or transported for a long period of time, particle aggregation and color change can be suppressed. Furthermore, a high-quality metal pigment composition in which particle aggregation and color change are suppressed can be suitably used as a raw material for water-based paints. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the present invention.

[0011] <Packaging> The package according to the present invention is a package in which a metal pigment composition containing metal particles and composite particles having one or more coating layers on the surface thereof is packed in a packaging container, and satisfies the following (1) to (4): (1) The composite particles have a scale-like shape. (2) Composite particles are those with a volume-based D when particle size distribution is measured using a laser diffraction particle size distribution analyzer. 50 is 1 to 30 μm. (3) The moisture content of the metallic pigment composition in the package is 0 to 1000 ppm relative to the mass of the metallic pigment composition. (4) The packaging container is made of thin chrome-plated steel sheet.

[0012] 1. Composite particles contained in metal pigment composition The metal pigment composition according to the present invention comprises a composite particle having a metal particle and one or more coating layers on the surface thereof. As used herein, the term "metal pigment composition" refers to a composition in which composite particles comprising metal particles and one or more coating layers on the surfaces thereof are dispersed in a solvent comprising a hydrophilic solvent, or the composite particles are accompanied by a solvent comprising a hydrophilic solvent, and may optionally contain other ingredients.

[0013] 1) Metal particles The composite particles contained in the metal pigment composition of the present invention include metal particles and one or more coating layers formed on the surfaces thereof.

[0014] The material of the metal particles constituting the composite particles is not particularly limited, and may be any metal known or used as a commercially available metal pigment, such as aluminum, aluminum alloy, zinc, iron, magnesium, nickel, copper, silver, tin, chromium, stainless steel, etc. In this specification, the metal of the metal particles constituting the composite particles includes not only simple metals but also alloys and intermetallic compounds. As described above, the metal particles may be composed of a single metal element, or may be composed of two or more metal elements. The metal particles in the present invention are preferably a metal containing aluminum as a main component, for example, aluminum or an aluminum alloy, and more preferably aluminum.

[0015] The metal particles are preferably scaly (flake-like). This allows the composite particles contained in the metal pigment composition of the present invention to also have a scaly shape, making it easier to more reliably obtain high hiding power, etc. The aspect ratio of the scaly metal particles (shape coefficient obtained by dividing the average particle size by the average thickness) is preferably 20 or more and 400 or less. When the aspect ratio of the metal particles is 20 or more, a higher sense of brilliance can be obtained. Furthermore, when the aspect ratio of the metal particles is 400 or less, mechanical strength is maintained and a stable color tone can be obtained. Here, the average thickness of the metal particles used in the present invention can be determined by known methods, for example, by calculating the water surface diffusion area and density of the metal particles.

[0016] The average particle size of the metal particles is D in the particle size distribution of the composite particles described later. 50 That is, when the volume distribution of the composite particles is measured using a laser diffraction particle size distribution analyzer, D 50 It is desirable to set the average particle size of the metal particles so that the average particle size is 1 μm or more and 30 μm or less. The average particle size of the metal particles can be controlled in the process of grinding, sieving, and filtering the raw atomized metal powder (e.g., aluminum powder) using a ball mill or the like by appropriately adjusting the particle size of the raw atomized metal powder, the mass per grinding ball when using a ball mill, the rotation speed of the grinding device, the degree of sieving and filter pressing, etc.

[0017] Furthermore, the metal particles do not necessarily have to be composed of metal only, and for example, particles in which the surface of inorganic particles such as synthetic resin particles, mica, glass, etc. is coated with metal can also be used as long as the effects of the present invention are not impaired. In the present invention, particles formed from aluminum or an aluminum alloy are particularly desirable in terms of high weather resistance, small specific gravity, ease of availability, etc.

[0018] Particularly suitable metal particles for the composite particles are aluminum flakes, which are commonly used as metallic pigments. Aluminum flakes are suitable for metallic pigments, having the surface properties, particle size, and shape required for metallic pigments, such as surface gloss, whiteness, and brilliance. Aluminum flakes are usually commercially available in paste form. Paste-like aluminum flakes typically contain scaly aluminum powder, as well as mineral spirits (aliphatic hydrocarbons) used during grinding, residual fatty acids, and organic solvents such as solvent naphtha and xylene. Paste-like aluminum flakes may be used as is, or may be used after previously removing fatty acids and other substances from the surface with an organic solvent or the like. In addition, the volume average particle diameter (D 50 ) is 1 μm or more and 30 μm or less, and preferably has an average thickness of 20 nm or more and 400 nm or less, so-called aluminum vapor deposition foil can also be used.

[0019] 2) Metal pigment composition The metallic pigment composition according to the present invention is characterized by satisfying the following physical property requirements. (1) The composite particles have a scale-like shape. (2) Volume-based D when measuring the particle size distribution of composite particles using a laser diffraction particle size distribution analyzer 50 is between 1 μm and 30 μm. (3) The moisture content of the metallic pigment composition in the package is 0 to 1000 ppm relative to the mass of the metallic pigment composition.

[0020] (1) The shape of the composite particles is scale-like. The composite particles of the metal pigment composition according to the present invention have a scaly (flake-like) shape. This allows a coating film formed using the metal pigment composition to exhibit high luminance, a high flip-flop effect, high hiding power, and the like. In this specification, the term "scaly" (flake-like) composite particles refers to composite particles having an average aspect ratio (shape coefficient calculated by dividing the average particle diameter by the average thickness) of 20 or more. From the viewpoint of achieving high luminance, a flip-flop effect, hiding power, and the like, the average aspect ratio of the scaly composite particles is preferably 20 or more and 400 or less. An average aspect ratio of 20 or more can provide sufficient luminance, while an average aspect ratio of 400 or less can maintain the mechanical strength of the flakes and achieve a stable color tone. The aspect ratio is more preferably 25 or more, and even more preferably 30 or more. It is more preferably 350 or less, and even more preferably 300 or less. The "composite particles" in the authenticity requirement (1) refer to the aggregates (aggregates) of multiple composite particles that are aggregated or adhered together.

[0021] Here, the average particle size for calculating the average aspect ratio of the composite particles is the volume-based D 50 This will be described in detail in the explanation of requirement (2) below. The average thickness for calculating the average aspect ratio of the composite particles is as described below.

[0022] (2) Volume-based D when measuring the particle size distribution of composite particles using a laser diffraction particle size distribution analyzer 50 is between 1 μm and 30 μm The volume-based D when measuring the particle size distribution of composite particles using a laser diffraction particle size distribution analyzer 50 The volumetric D is 1 μm or more and 30 μm or less. This allows a coating film formed using the metal pigment composition to exhibit high brightness, a high flip-flop effect, high hiding power, etc., and also suppresses aggregation of the individual particles constituting the metal pigment composition, thereby reducing the aggregation. 50 is also commonly referred to as the median diameter.

[0023] From the viewpoint of obtaining such high brightness, high flip-flop effect, high hiding power, and small aggregation of individual particles, the volume-based D 50 The lower limit of is 1 μm or more, preferably 2 μm or more, more preferably 3 μm or more, and the upper limit is 30 μm or less, preferably 25 μm or less, more preferably 20 μm or less. The "composite particles" in the authenticity requirement (2) refer to the aggregates (aggregates) of multiple composite particles that are aggregated or adhered together.

[0024] Here, the volume-based D when the particle size distribution of composite particles is measured using a laser diffraction particle size distribution analyzer is 50 indicates the particle size at 50% cumulative degree in the volume cumulative particle size distribution. The laser diffraction particle size distribution meter is not particularly limited, but for example, "LA-300" (manufactured by Horiba Ltd.) can be used. Mineral spirits can be used as the measurement solvent. For example, a metal pigment composition containing composite particles as a sample is subjected to ultrasonic dispersion for 2 minutes as a pretreatment, then placed in a dispersion tank and confirmed to be properly dispersed, and then D 50 can be measured. This method cannot measure the particle size of the composite particles in a resin composition obtained by adding a resin to a metal pigment composition. Therefore, as an alternative method, a method can be adopted in which the composite particles in the resin composition are photographed from the surface of the coating film using, for example, an optical microscope or a laser microscope, and the particle size is determined by obtaining the distribution of circle-equivalent diameters using commercially available image analysis software.

[0025] D based on the volume of the composite particles contained in the metal pigment composition 50In the manufacturing method of a metal pigment composition described below, the particle size of the raw atomized metal powder (e.g., aluminum powder) is milled and sieved / filtered using a ball mill or the like, by appropriately adjusting the particle size of the raw atomized metal powder, the mass per milling ball when a ball mill is used, the rotation speed of the milling device, the degree of sieving and filter pressing, etc.; and in the step of coating, for example, with a silicon compound-containing layer (and other coating layers as necessary), by appropriately adjusting the type of organosilicon compound used, the pH, concentration, stirring temperature, stirring time, type of stirring device, and stirring power / degree (type and diameter of stirring blades, rotation speed, presence or absence of external stirring, etc.) in the coating step (including the coating step if the organosilicon compound is hydrolyzed).

[0026] The composite particles, which are comprised of metal particles and one or more coating layers on the surfaces of the metal particles contained in the metal pigment composition of the present invention, desirably have an average thickness of 20 nm to 400 nm, which, in combination with the satisfaction of the above requirements (1) and (2), allows a coating film formed using the metal pigment composition to exhibit high luminance, a high flip-flop effect, high hiding power, etc.

[0027] From the above viewpoint, the average thickness of the composite particles has a desirable lower limit of 20 nm or more, preferably 25 nm or more, and more preferably 30 nm or more, and a desirable upper limit of 400 nm or less, preferably 350 nm or less, and more preferably 300 nm or less. The average thickness of a "composite particle" refers to the average thickness of the aggregate (aggregate) when multiple composite particles are aggregated or adhered together.

[0028] The average thickness of the composite particles can be calculated from the water surface diffusion area and density of the composite particles. The water surface diffusion area refers to the area occupied by dry composite particles per unit mass when the dried composite particles are uniformly dispersed on the water surface using the leafing phenomenon and coated without gaps. The water surface diffusion area can be measured according to the provisions of JIS K5906:1998. However, in the case of the composite particles of the present invention, if the surface is highly hydrophilic, it may be difficult to determine the water surface diffusion area. In this case, the average thickness of the composite particles can be measured according to the method described in the Examples below. That is, the composite particles are dispersed in a mixture of an alcoholic solvent such as methoxypropanol and water to form a coating (thin film), and the thickness of the composite particles (100 or more) can be observed using a scanning electron microscope (SEM) to determine the average thickness of the composite particles.

[0029] The average thickness of the composite particles contained in the metal pigment composition is D 50 Similarly, in the manufacturing method of a metal pigment composition described below, in the step of grinding, sieving, and filtering a raw atomized metal powder (e.g., aluminum powder) using a ball mill or the like, the particle size of the raw atomized metal powder, the mass per grinding ball when a ball mill is used, the rotation speed of the grinding device, the degree of sieving and filter pressing, etc. can be appropriately adjusted; and in the step of coating, for example, with a silicon compound-containing layer (and other coating layers as necessary), the type of organosilicon compound used, the pH, concentration, stirring temperature, stirring time, type of stirring device, and stirring power / degree (e.g., type and diameter of stirring blades, rotation speed, presence or absence of external stirring) in the coating step (including the coating step if the organosilicon compound is hydrolyzed and used).

[0030] (3) The moisture content of the metallic pigment composition in the package is 0 to 1000 ppm relative to the mass of the metallic pigment composition. The moisture content of the metal pigment composition in the package of the present invention is (0 ppm or more) to 1000 ppm or less (by mass) of the metal pigment composition. By maintaining such a moisture content, it is possible to further suppress the aggregation of composite particles of the metal pigment composition in the package and the progression of color changes. The moisture content is more preferably 500 ppm or less, even more preferably 300 ppm or less, and particularly preferably 200 ppm or less. There is no lower limit for the moisture content, and the lower the better.

[0031] To achieve such a moisture content, for example, in the case of forming a silicon compound-containing layer, after the process of forming a silicon compound-containing layer (and / or optional other coating layer) on the metal particles in the process of producing the metal pigment composition, known processes such as washing and solid-liquid separation are carried out. In this process, for example, the dispersion is washed with an organic solvent having a moisture content of 1000 ppm or less, and then filtered using a filter. In some cases, this process is preferably repeated multiple times to remove water and unreacted materials from the composition containing the composite particles. If necessary, the cake containing the composite particles may then be subjected to a heat dehydration treatment in a gas atmosphere such as nitrogen with a low moisture content, for example, at a temperature in the range of 100 to 500°C. As described below, the composite particles recovered in this manner typically comprise a metal pigment composition containing a small amount of solvent, including water and hydrophilic solvent, used in the production process.

[0032] Furthermore, when adjusting the solid content of the composition, it is also desirable to use an organic solvent (such as a hydrophilic solvent described below) with a moisture content of 1000 ppm or less. The water content of the organic solvent used for washing or adjusting the solid content is preferably 1000 ppm or less, more preferably 500 ppm or less, even more preferably 300 ppm or less, and particularly preferably 200 ppm or less.

[0033] Moisture may also be present in the gas phase of the package. The moisture in the gas phase of the package originates from the moisture contained in the metal pigment composition packaged in the packaging container and from the moisture in the air outside the volume of the packaging container. If there is a large amount of moisture in the gas phase, the metal pigment composition will absorb this moisture, resulting in a high moisture content. For this reason, it is preferable to use dry air when placing the metal pigment composition in the packaging container. Another preferred method is to replace the gas phase with dry air before closing the lid on the packaging container. When dry air is used when placing the metal pigment composition in the packaging container, or when the gas phase is replaced with dry air before closing the lid on the packaging container and simultaneously sealing it, the moisture content in the package is substantially equal to the moisture content in the metal pigment composition, and the moisture content in the metal pigment composition does not increase significantly during storage. The moisture content in the metal pigment composition can be measured using the method described below in the Examples.

[0034] 3) Covering layer The metal pigment composition of the present invention must have one or more coating layers formed on the surface of the metal particles that form the core of the composite particles. Examples of coating layers include those containing at least one of silicon compounds, metals (alkali metals; alkaline earth metals; manganese, iron, cobalt, nickel, copper, silver, and other metals), metal oxides (titanium oxide, zirconium oxide, iron oxide, and other metals), metal hydrates, and resins (acrylic resins, alkyd resins, polyester resins, polyurethane resins, polyvinyl acetate resins, nitrocellulose resins, fluororesins, and other synthetic resins). Among these, it is desirable for the coating layer to contain a silicon compound, particularly a layer composed of a structure containing Si-O bonds. This can suppress gas generation in aqueous paints, provide good storage stability (i.e., corrosion resistance), and impart excellent water resistance when formed into a coating film. Two or more coating layers may be formed, and in this case, it is preferable for at least one layer to contain a silicon compound.

[0035] The silicon compound-containing layer is preferably a layer composed of a compound containing a Si-O- bond (siloxane bond). Examples of such a layer include a layer containing at least one of polysiloxane formed by hydrolysis and condensation of an organosilicon compound, a silane-based compound, and a silicon oxide. Examples of such a compound include, in addition to polysiloxane, a silane-based compound [H3SiO(H2SiO)] n Examples include silicon oxides such as SiO2 and SiO2·nH2O (where n is any positive integer), as well as SiO2 (where n is any positive integer). These silane compounds and silicon oxides may be either crystalline or amorphous, but are particularly preferably amorphous. Therefore, a layer containing amorphous silica can also be suitably used as a layer containing silicon oxide (such as silica).

[0036] In addition, the layer composed of a compound containing an Si-O bond may be a layer formed using an organosilicon compound (including a silane coupling agent) as a starting material. In this case, the silicon compound-containing layer may contain an organosilicon compound or a component derived therefrom within a range that does not impair the effects of the present invention. In a typical example, the layer composed of a compound containing an Si-O bond can be formed by hydrolyzing an organosilicon compound. The silicon compound-containing layer may contain additives, impurities, etc. other than the silicon compound, as long as the properties of the present invention are not impaired.

[0037] The coating layer of the composite particles contained in the metal pigment composition according to the present invention is preferably particularly hydrophilic. Composite particles typically form metal pigment compositions in the form of a dispersion in an aqueous solvent (water or a mixed solvent containing water and an organic solvent). However, if the coating layer has a hydrophilic surface, the composite particles can be highly dispersed in such an aqueous solvent. Furthermore, because compounds containing Si-O bonds (polysiloxane, amorphous silica, etc.) are highly stable in aqueous solvents, it is possible to provide a metal pigment composition containing composite particles that are highly stable in aqueous solvents. From this perspective, it is desirable that at least the outermost layer of the composite particles contained in the metal pigment composition according to the present invention be a silicon compound-containing layer (particularly a layer composed of a compound containing Si-O bonds). When the coating layer is composed of multiple layers, in addition to the outermost silicon compound-containing layer, a silicon compound-containing layer (particularly an Si-O-based coating layer) may be separately formed as a layer other than the outermost layer.

[0038] The thickness of the coating layer of each composite particle is preferably generally about 10 to 80 nm, particularly 15 to 70 nm, and even more preferably 20 to 60 nm, so that the average thickness of the composite particles is in the desired range of 20 to 400 nm, as described above. A coating layer thickness of 10 nm or more can provide a coating film that has sufficient water resistance and suppresses corrosion or discoloration of metal particles in aqueous paints. On the other hand, a coating layer thickness of about 80 nm or less can maintain high levels of brightness, distinctness, and hiding power of the coating film.

[0039] When the coating layer of each composite particle contains a silicon compound-containing layer, the thickness of the layer may be typically in the range of 10 nm to 80 nm, and preferably in the range of 15 nm to 70 nm, from the viewpoint of exhibiting the functionality of the layer, so that the average thickness of the composite particles is in the desirable range of 20 nm to 400 nm.

[0040] Specific examples of organosilicon compounds that can be used in the present invention are further described below, but the organosilicon compounds are not limited to these specific examples. The organosilicon compound may contain at least one organosilicon compound represented by the following general formula (1) and at least one silane coupling agent selected from the group consisting of silane coupling agents represented by any of the following general formulas (2), (3), and (4), and partial condensates thereof. Si(OR 1 )4··· (1) (In the formula, R 1 is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, and R 1 may all be the same, some may be the same, or all may be different.) R 2 m Si(OR 3 ) 4-m (2) (In the formula, R 2 is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms which may optionally contain a halogen group, and R3 is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. 2 and R 3 may be the same or different, and R 2 , or R 3 When there are two or more, they may all be the same, some may be the same, or all may be different. 1≦m≦3. R 4 p R 5 q Si(OR 6 ) 4-p-q (3) (In the formula, R 4 is a group containing a reactive group capable of chemically bonding with other functional groups, and R 5 is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, which may optionally contain a halogen group; R 6 is a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. 4 , R 5 , or R 6 When there are two or more, they may all be the same, some may be the same, or all may be different. 1≦p≦3, 0≦q≦2, and 1≦p+q≦3. R 7 r SiCl 4-r(4) (In the formula, R 7 is a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, which may optionally contain a halogen group; R 7 When there are two or more, they may all be the same, some may be the same, or all may be different. 0≦r≦3.

[0041] R in Equation (1) 1 Examples of hydrocarbon groups in include methyl, ethyl, propyl, butyl, hexyl, octyl, etc., which may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl are particularly preferred. In addition, the four R 1 may all be the same, some may be the same, or all may be different.

[0042] Preferred examples of such organosilicon compounds of formula (1) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, etc. Among these, tetraethoxysilane is particularly preferred.

[0043] R in Equation (2) 2 Examples of hydrocarbon groups in the formula (2) include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, naphthyl, etc., which may be branched or linear and may contain halogen groups such as fluorine, chlorine, or bromine. Among these, hydrocarbon groups having 1 to 18 carbon atoms are particularly preferred. Furthermore, when there are two or more R2s, they may all be the same, some may be the same, or all may be different. The number of R2s in the molecule in formula (2) is m = 1 to 3, i.e., 1 to 3, but it is more preferred that m = 1 or 2.

[0044] R in Equation (2) 3Examples of hydrocarbon groups in R include methyl, ethyl, propyl, butyl, hexyl, octyl, etc., which may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl are particularly preferred. 3 When there are two or more of them, they may all be the same, some may be the same, or all may be different.

[0045] Preferred examples of such organosilicon compounds (silane coupling agents) of formula (2) include methyltrimethoxysilane, methyltriethoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyldibutoxysilane, trimethylmethoxysilane, trimethylethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyltributoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltributoxysilane, dibutyldimethoxysilane, dibutyldiethoxysilane, dibutyldibutoxysilane, isobutyltrimethoxysilane, isobutyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane, octyltrimethoxysilane, octyltriethoxy ... Examples thereof include isethoxysilane, dioctyldimethoxysilane, dioctyldiethoxysilane, dioctylethoxybutoxysilane, decyltrimethoxysilane, decyltriethoxysilane, didecyldimethoxysilane, didecyldiethoxysilane, octadecyltrimethoxysilane, octadecyltriethoxysilane, dioctadecyldimethoxysilane, dioctadecyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, trifluoropropyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, and 3-chloropropyltributoxysilane.

[0046] R in Equation (3) 4 Examples of reactive groups capable of chemically bonding with other functional groups in include vinyl groups, epoxy groups, styryl groups, methacryloxy groups, acryloxy groups, amino groups, ureido groups, mercapto groups, polysulfide groups, and isocyanate groups. Also, R 4 When there are two or more R in a molecule, they may all be the same, some may be the same, or all may be different. 4 In formula (3), the number of p is 1 to 3, that is, 1 to 3, but p=1 is more preferable.

[0047] R in Equation (3) 5 Examples of hydrocarbon groups include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, naphthyl, etc., which may be branched or straight chain and may contain halogen groups such as fluorine, chlorine, and bromine. Among these, hydrocarbon groups having 1 to 18 carbon atoms are particularly preferred. 5 When there are two or more of them, they may all be the same, some may be the same, or all may be different.

[0048] R in Equation (3) 6 Examples of hydrocarbon groups in R include methyl, ethyl, propyl, butyl, hexyl, octyl, etc., which may be branched or linear. Among these hydrocarbon groups, methyl, ethyl, propyl, and butyl are particularly preferred. 6 When there are two or more of them, they may all be the same, some may be the same, or all may be different.

[0049] Preferred examples of such organosilicon compounds (silane coupling agents) of formula (3) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-amino Examples of suitable silanes include propylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, and 3-isocyanatopropyltriethoxysilane.

[0050] R in equation (4) 7 Examples of hydrocarbon groups in R include methyl, ethyl, propyl, butyl, hexyl, octyl, decyl, dodecyl, oleyl, stearyl, cyclohexyl, phenyl, benzyl, naphthyl, etc., which may be branched or linear and may contain halogen groups such as fluorine, chlorine, or bromine. Among these, hydrocarbon groups having 1 to 12 carbon atoms are particularly preferred. 7When there are two or more R in a molecule, they may all be the same, some may be the same, or all may be different. 7 In formula (4), the number of is r=0 to 3, that is, 0 to 3, but r=1 to 3 is more preferable.

[0051] Preferred examples of such organosilicon compounds (silane coupling agents) of formula (4) include methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, octyldimethylchlorosilane, phenyltrichlorosilane, vinyltrichlorosilane, and tetrachlorosilane.

[0052] The organosilicon compound represented by the general formula (1) may be used alone or in combination of two or more. Similarly, the silane coupling agent represented by any of the general formulas (2), (3), and (4) may be used alone or in combination of two or more. When using two or more in combination, only two or more silane coupling agents represented by any of the general formulas (2), (3), and (4) may be used in combination, or silane coupling agents represented by two or more different general formulas may be used in combination.

[0053] The hydrolyzate and / or condensation reaction product of an organosilicon compound can be obtained by stirring and mixing the organosilicon compound with an amount of water required for the hydrolysis reaction and a hydrolysis catalyst, optionally in the presence of a hydrophilic solvent.

[0054] As a raw material for the hydrolysis reaction and / or condensation reaction to obtain a hydrolyzate of an organosilicon compound and / or a condensation reaction product thereof, a partially condensed oligomer may be used in advance. The condensation reaction of the hydrolyzate of the organosilicon compound may be carried out simultaneously with the hydrolysis reaction of the organosilicon compound, or may be carried out in separate steps, using different catalysts if necessary. In this case, heating may be performed as necessary.

[0055] It is preferable that at least one of the coating layers of the composite particles contained in the metal pigment composition according to the present invention is a silicon compound-containing layer, but coating layers other than the silicon compound-containing layer (hereinafter referred to as "other coating layers") may be formed alone or together with the silicon compound-containing layer. The other coating layer may contain at least one of metals (alkali metals; alkaline earth metals; manganese, iron, cobalt, nickel, copper, silver, etc.), metal oxides (titanium oxide, zirconium oxide, iron oxide, etc.), metal hydrates, and resins (synthetic resins such as acrylic resins, alkyd resins, polyester resins, polyurethane resins, polyvinyl acetate resins, nitrocellulose resins, and fluororesins). Examples of other coating layers that can be formed include molybdenum-containing coatings and phosphate compound coatings. The provision of other coating layers can improve the corrosion resistance of the metal particles.

[0056] When another coating layer is formed, it is preferably formed between the metal particles and the silicon compound-containing layer. Therefore, for example, a layer structure of "metal particles / other coating layer / silicon compound-containing layer" can be preferably adopted. Examples of molybdenum-containing coatings include, but are not limited to, those disclosed in JP 2003-147226 A, WO 2004 / 096921 A, Japanese Patent No. 5979788, and Japanese Patent No. 2019-151678 A. Examples of phosphate compound coatings include those disclosed in Japanese Patent No. 4633239 A. Preferred examples of molybdenum-containing materials constituting the molybdenum-containing coating include the mixed coordination heteropolyanion compounds disclosed in JP 2019-151678 A.

[0057] In another variation, other coating layers can be formed on the outside of the metal particles and the silicon compound-containing layer. In yet another variation, components of the silicon compound-containing layer (such as a molybdenum-containing compound or a phosphate compound) can be included in the silicon compound-containing layer along with the silicon compound.

[0058] The mixed coordination heteropolyanion compound used to form a coating layer other than the silicon compound-containing layer of the composite particles contained in the metal pigment composition of the present invention (typically a molybdenum-containing coating) is not particularly limited, but specific examples include the following. The mixed coordination heteropolyanion of the mixed coordination heteropolyanion compound that can be used has a structure in which some of the polyatoms of a heteropolyanion consisting of one type of element are substituted with another element, and exhibits physical properties different from those of a mixture of the individual heteropolyanions.

[0059] When expressed as a chemical formula, a mixed coordination heteropolyanion is represented as [X p M q N r O s ] t The heteropolyanion is expressed as [X p M q O s ] t and further isopolyanion [M q O s ] t However, the heteroatom X represents an element of Group IIIB, IVB, or VB, such as B, Si, Ge, P, or As, with B, Si, or P being preferred. The polyatoms M and N represent transition metals, such as Ti, Zr, V, Nb, Ta, Mo, or W, with Ti, Zr, V, Nb, Mo, or W being preferred. Also, p, q, r, and s represent the number of atoms, and t represents the oxidation number.

[0060] Since heteropolyanion compounds have a variety of structures, mixed coordination heteropolyanion compounds can have even more structures. Representative and preferred mixed coordination heteropolyanion compounds include the following mixed coordination heteropolyacid: H3PW x Mo 12-x O 40 ·nH2O (phosphotungstomolybdic acid·n hydrate), H 3+x PV x Mo 12-x O 40 ·nH2O (phosphorus vanadomolybdic acid·n-hydrate), H4SiWx Mo 12-x O 40 ·nH2O (silicotungstomolybdic acid·n hydrate), H 4+x SiV x Mo 12-x O 40 Examples include silyl vanadomolybdic acid n-hydrate (where 1≦x≦11, n≧0).

[0061] Among these heteropolyanion compounds, a preferred example is H3PW3Mo9O 40 nH2O, H3PW6Mo6O 40 nH2O, H3PW9Mo3O 40 nH2O, H4PV1Mo 11 O 40 nH2O, H6PV3Mo9O 40 nH2O, H4SiW3Mo9O 40 nH2O, H4SiW6Mo6O 40 nH2O, H4SiW9Mo3O 40 nH2O, H5SiV1Mo 11 O 40 nH2O, H7SiV3Mo9O 40 Examples include mixed coordination heteropolyacids such as nH2O (where n≧0).

[0062] The mixed coordination heteropolyanion compound may be used in the form of an acid (so-called mixed coordination heteropolyacid) or in the form of a (partial or complete) salt with a specific cation as the counter ion. When a mixed coordination heteropolyanion compound is used in the form of a salt having a specific cation as a counter ion, the counter cation source can be at least one selected from alkali metals such as lithium, sodium, potassium, rubidium, and cesium; alkaline earth metals such as magnesium, calcium, strontium, and barium; metals such as manganese, iron, cobalt, nickel, copper, zinc, silver, cadmium, lead, and aluminum; inorganic components such as ammonia; and organic components such as amine compounds. Among the inorganic components, salts of alkali metals, alkaline earth metals, and ammonia are preferred.

[0063] Furthermore, when at least one selected from the alkali metals, alkaline earth metals, and ammonia is used as a counter cation source, H3PW x Mo 12-x O 40 ·nH2O (phosphotungstomolybdic acid·n hydrate), H 3+x PV x Mo 12-x O 40 ·nH2O (phosphorus vanadomolybdic acid·n-hydrate), H4SiW x Mo 12-x O 40 ·nH2O (silicotungstomolybdic acid·n hydrate), H 4+x SiV x Mo 12-x O 40 It is more preferable to use it in the form of a salt with at least one selected from the group consisting of carboxymethyl methyl acrylate, ...

[0064] Furthermore, amine compounds, which are organic components, are also preferably used as sources of counter cations for mixed coordination heteropolyanion compounds, and specific examples thereof are preferably those represented by the following general formula (5). (R 8 -N(-R 10 )-) n -R 9 (5) (In the formula, R 8 , R 9 and R 10 may be the same or different and are a hydrogen atom or a monovalent or divalent hydrocarbon group having 1 to 30 carbon atoms, which may optionally contain an ether bond, an ester bond, a hydroxyl group, a carbonyl group, or a thiol group, and optionally R 8 and R 9 may be taken together to form a 5- or 6-membered cycloalkyl group, or a 5- or 6-membered ring which may additionally contain nitrogen or oxygen atoms as bridging members, or optionally R 8 , R 9 and R 10 R may be taken together to form a multi-membered ring which may contain one or more additional nitrogen and / or oxygen atoms as bridging members. 8 , R9 and R 10 cannot be a hydrogen atom at the same time. n represents an integer from 1 to 2.)

[0065] Examples of the amine compound that is a counter cation source for the mixed coordination heteropolyanion compound include linear or branched primary amines, linear, branched, or asymmetric secondary amines, and tertiary amines having linear, branched, or mixed hydrocarbon groups, as well as alicyclic primary amines, primary amines having an aromatic ring substituent, alicyclic secondary amines, secondary amines having an aromatic ring substituent, alicyclic asymmetric secondary amines, alicyclic tertiary amines, tertiary amines having an aromatic ring substituent, amines having an ether bond, alkanolamines, diamines, cyclic amines, aromatic amines, and any mixtures thereof.

[0066] Among these amine compounds, preferred examples include at least one selected from primary, secondary, or tertiary amines or alkanolamines having a linear or branched alkyl group having 4 to 20 carbon atoms. Specific examples include butylamine, hexylamine, cyclohexylamine, octylamine, tridecylamine, stearylamine, dihexylamine, di-2-ethylhexylamine, linear or branched ditridecylamine, distearylamine, tributylamine, trioctylamine, linear or branched tritridecylamine, tristearylamine, N,N-dimethylethanolamine, N-methyldiethanolamine, triethanolamine, morpholine, etc.

[0067] At least one selected from the amine compounds represented by the general formula (5) and H3PW x Mo 12-x O 40 ·nH2O (phosphotungstomolybdic acid·n hydrate), H 3+x PV x Mo 12-x O 40 ·nH2O (phosphorus vanadomolybdic acid·n-hydrate), H4SiW x Mo 12-x O 40 ·nH2O (silicotungstomolybdic acid·n hydrate), H4+x SiV x Mo 12-x O 40 It is more preferable to use it in the form of a salt with at least one selected from the group consisting of carboxymethyl methyl acrylate, ...

[0068] Among the above mixed coordination heteropolyanion compounds, H3PW x Mo 12-x O 40 ·nH2O (phosphotungstomolybdic acid·n hydrate), H 3+x PV x Mo 12-x O 40 ·nH2O (phosphorus vanadomolybdic acid·n-hydrate), H4SiW x Mo 12-x O 40 Mixed coordination heteropolyacids such as silicotungstomolybdic acid n-hydrate (nH2O) or organic amine salts of these mixed coordination heteropolyacids are most preferred.

[0069] The coating layer other than the silicon compound-containing layer of the composite particle contained in the metal pigment composition according to the present invention (if formed) may be a layer containing another corrosion inhibitor to further improve the corrosion resistance of the core metal particle (preferably an aluminum particle or an aluminum alloy particle). The corrosion inhibitor to be added is not particularly limited, and any known corrosion inhibitor can be used. The amount used may be within a range that does not impair the desired effects of the present invention. Examples of such corrosion inhibitors include acidic phosphate esters, dimer acids, organic phosphorus compounds, and metal salts of molybdic acid.

[0070] The silicon compound-containing layer and / or other coating layer of the composite particles contained in the metal pigment composition, or as a separate layer, may further contain an organic oligomer or polymer from the viewpoint of adhesion and chemical resistance when a coating film is formed. In addition, from the viewpoint of storage stability, at least one selected from the group consisting of inorganic phosphoric acids and their salts, and acidic organic (phosphorous) esters and their salts may be contained in the silicon compound-containing layer and / or other coating layer of the composite particle, or as a separate layer. These compounds are not particularly limited, but for example, those disclosed in JP 2019-151678 A can be used.

[0071] 2.Method for producing metal pigment composition The metal pigment composition of the present invention can be suitably produced by a production method including the steps of forming scaly metal particles using a method commonly used in the pigment industry, followed by steps such as sieving (classification), filtration, washing, and mixing to produce the metal particles, and then forming a coating layer under stirring using a solvent containing water and / or a hydrophilic solvent. More specifically, the following methods can be mentioned, but are not limited to these. Hereinafter, a typical example will be described in which at least one coating layer of the composite particles contained in the metal pigment composition is a silicon compound-containing layer.

[0072] The metal pigment composition of the present invention can be suitably produced, for example, by a method including a step of forming a silicon compound-containing layer on the surface of the metal particles (silicon compound-containing layer forming step) by hydrolysis / (partial) condensation reaction of the organosilicon compound in a mixed liquid containing (a) metal particles, (b) at least one silicon-containing raw material containing an organosilicon compound, (c) a solvent (water and / or a hydrophilic solvent), and, if necessary, other optional components. This step is usually carried out under stirring.

[0073] 1) Crushing, sieving and filtering process Here, an example will be described in which aluminum powder is used as the metal particles. The aluminum powder is generally obtained by pulverizing atomized aluminum powder and / or aluminum foil in the presence of a grinding aid and an inert solvent using a method commonly used in the pigment industry, such as a dry ball mill method, a wet ball mill method, an attritor method, or a stamp mill method, to form the aluminum powder into flakes, and then further performing any necessary steps, such as sieving (classification), filtration, washing, and mixing.

[0074] Examples of grinding aids include fatty acids, fatty amines, fatty amides, and fatty alcohols. Generally, oleic acid, stearic acid, and stearylamine are preferred. Examples of inert solvents include hydrophobic solvents such as mineral spirits, solvent naphtha, LAWS, HAWS, toluene, and xylene, which can be used alone or in combination. The grinding aids and inert solvents are not limited to these. As the pulverization step, pulverization by a wet ball mill method is preferred from the viewpoint of preventing dust explosions and ensuring safety.

[0075] When aluminum particles are used as the metal particles in the production of the metal pigment composition of the present invention, commercially available paste-like aluminum flakes obtained through such pulverization, sieving, and filtration can be used. The paste-like aluminum flakes may be used as they are, or may be used after previously removing fatty acids and the like from the surface with an organic solvent or the like.

[0076] In addition, as the metal particles for producing the metal pigment composition of the present invention, so-called vapor-deposited aluminum foil pigments can also be used, which are produced by peeling off a metal layer deposited on a carrier material such as a resin film by physical vapor deposition (PVD) from the carrier material and pulverizing it.

[0077] 2) Formation of silicon compound-containing layer The mixture containing the above-mentioned (a) metal particles, (b) silicon-containing raw material containing at least one organosilicon compound, and (c) solvent, as well as other optional components, can be prepared by mixing these components. The order of mixing is not particularly limited.

[0078] The metal particles may be any of the above-mentioned metal particles, but aluminum or aluminum alloy particles are particularly suitable. Furthermore, as described above, it is preferable to use flaky metal particles. Known or commercially available metal particles (typically, paste-like aluminum flakes) may be used. The content (solid content) of the metal particles in the mixed liquid is not particularly limited, and can be set appropriately depending on the type, particle size, etc. of the metal particles used.

[0079] The silicon-containing raw material is an organosilicon compound, and although not limited thereto, the organosilicon compound may preferably be any of those listed above. At least one of the organosilicon compounds represented by the above formula (1) (typical example is tetraalkoxysilane) and / or their condensates, and the silane coupling agents represented by any of the above formulas (2) to (4) can be suitably used. Hereinafter, an example will be described in which tetraalkoxysilane is used as the organosilicon compound represented by the above formula (1). Note that tetraalkoxysilane and / or its condensate may hereinafter be collectively referred to simply as "tetraalkoxysilane."

[0080] When a tetraalkoxysilane represented by the formula (1) and a silane coupling agent represented by any one of the formulae (2) to (4) are used in combination, a method (referred to as "method 1") in which both are mixed and used can be employed. Alternatively, a method (referred to as "method 2") can be employed that includes a step of treating metal particles with one agent to form a first silicon compound-containing layer, and then treating metal particles with the other agent to form a second silicon compound-containing layer.

[0081] An example of the first method is a method including a step of forming a silicon compound-containing layer by appropriately adjusting the pH of a mixed solution containing metal particles, a tetraalkoxysilane represented by the above formula (1), and a silane coupling agent represented by any one of the above formulas (2) to (4), thereby causing a hydrolysis / condensation reaction of the tetraalkoxysilane and the silane coupling agent.

[0082] The second method includes, for example, a method including a step of appropriately adjusting the pH of a mixed solution containing metal particles and a tetraalkoxysilane represented by the above formula (1) to cause a hydrolysis / condensation reaction of the tetraalkoxysilane to form a first silicon compound-containing layer (e.g., a silica coating made of amorphous silica) on the surface of the metal particles, and a step of adjusting the pH of a mixed solution containing metal particles and a silane coupling agent represented by any one of the above formulas (2) to (4) to cause a hydrolysis / condensation reaction of the silane coupling agent to form a second silicon compound-containing layer on the surface of the first silicon compound-containing layer.

[0083] The amount of the tetraalkoxysilane represented by the formula (1) or its condensate used can be appropriately set depending on the type of tetraalkoxysilane used, etc. For example, from the viewpoint of the coating treatment effect and from the viewpoint of suppressing aggregation of the metal particles or a decrease in brightness, the amount used may be 2 to 200 parts by mass, and more preferably 5 to 100 parts by mass, per 100 parts by mass of the metal particles (solid content).

[0084] The amount of the silane coupling agent represented by any one of the above formulas (2) to (4) used is not particularly limited, but may usually be about 0.1 to 20 parts by mass, and preferably 1 to 10 parts by mass, per 100 parts by mass of metal particles (solid content). By using an amount of about 0.1 to 20 parts by mass, the desired coating treatment effect and desirable coating film properties can be obtained.

[0085] The solvent in the mixed solution, i.e., the solvent for the hydrolysis reaction and / or condensation reaction of the organosilicon compound, can be appropriately selected depending on the type of silicon-containing raw material used, but typically water, a hydrophilic organic solvent, or a mixed solvent thereof can be used. The use of these solvents can improve the uniformity of the reaction and the uniformity of the resulting hydrolyzate and / or condensation reaction product. In an embodiment in which a silicon compound-containing layer is formed directly on metal particles, it is particularly preferable that the solvent in the mixed solution contains a hydrophilic organic solvent in order to prevent the reaction between the metal particles and water from proceeding too quickly. In the present invention, a mixed solvent of water and a hydrophilic organic solvent can be preferably used.

[0086] The hydrophilic organic solvent is not particularly limited, but examples thereof include alcohols such as methanol, ethanol, propanol, butanol, isopropanol, and octanol; ether alcohols and esters thereof such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether; glycols such as ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, polyoxyethylene glycol, polyoxypropylene glycol, and ethylene propylene glycol; ethyl cellosolve, butyl cellosolve, acetone, methoxypropanol, ethoxypropanol, and other alkoxy alcohols. These may be used alone or in combination of two or more.

[0087] In addition, when a mixed solvent of water and a hydrophilic organic solvent is used as the solvent, the ratio of the two is not particularly limited. In an embodiment in which a silicon compound-containing layer is formed directly on metal particles, in order to prevent the reaction between the metal particles and water from proceeding too quickly, it is preferable that the water content be 20% by mass or less, with the total of both being 100% by mass, before adding the silicon compound. In this case, the lower limit of the water content is not limited.

[0088] The amount of solvent used in the silicon compound-containing layer formation process (excluding the amount of solvent used for pre-dispersion of metal particles, if any) is not limited, but is typically approximately 100 to 10,000 parts by mass per 100 parts by mass of metal particles (solid content), and preferably 200 to 1,000 parts by mass. Using 100 parts by mass or more of solvent suppresses an increase in the viscosity of the mixed liquid (slurry) and enables appropriate stirring. Furthermore, using 10,000 parts by mass or less of solvent can prevent the recovery and recycling costs of the treatment liquid from becoming too high. In the case of the second method described above, the amount of solvent used here refers to the total amount of solvent used to form the first silicon compound-containing layer and the second silicon compound-containing layer.

[0089] The mixed solution may contain other additives as needed within the range that does not impair the effects of the present invention. Examples of such additives include catalysts such as hydrolysis catalysts and dehydration condensation catalysts, surfactants, and metal corrosion inhibitors. Among these, a hydrolysis catalyst can be preferably used. The incorporation of a hydrolysis catalyst not only adjusts the pH of the mixed solution but also efficiently hydrolyzes and dehydration-condenses the organosilicon compound, thereby enabling efficient and reliable formation of a silicon compound-containing layer on the surface of the metal particles.

[0090] The hydrolysis catalyst may be any known or commercially available one, and is not particularly limited. Examples of the hydrolysis catalyst include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; organic acids such as benzoic acid, acetic acid, and chloroacetic acid; and phosphonic acids such as vinylphosphonic acid, 2-carboxyethanephosphonic acid, 2-aminoethanephosphonic acid, and octanephosphonic acid. These hydrolysis catalysts may be used alone or in combination of two or more.

[0091] Examples of hydrolysis catalysts that can be used include inorganic alkalis such as ammonia, sodium hydroxide, and potassium hydroxide; inorganic alkali salts such as ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate; amines such as monomethylamine, dimethylamine, trimethylamine, pyridine, and aniline; and salts of organic acids such as ammonium formate, ammonium acetate, monomethylamine formate, and aniline acetate. These hydrolysis catalysts can be used alone or in combination of two or more.

[0092] In preparing the above-mentioned mixed solution, these components may be mixed so as to be uniform in the mixed solution, and the order of mixing them is not particularly limited. In the production of the metal pigment composition according to the present invention, the preparation of the mixed liquid is preferably carried out under appropriate stirring.

[0093] The agitator for stirring the mixture is not particularly limited, and any known agitator capable of efficiently and uniformly stirring the mixture containing aluminum particles and an organosilicon compound can be used.Specific examples include kneaders, kneading machines, rotary vessel agitators, stirred reaction vessels, V-type agitators, double cone agitators, screw mixers, sigma mixers, flash mixers, airflow agitators, ball mills, edge runners, etc.A further explanation of the agitator will be given later.

[0094] The temperature of the mixed liquid containing the metal particles and the organosilicon compound when being stirred is usually about 10 to 80°C, and preferably 20 to 70°C.

[0095] The stirring time of the mixed solution is not particularly limited as long as it is a time sufficient for forming the desired silicon compound-containing layer.

[0096] Whether the first or second method is adopted, the hydrolyzate and / or condensate of the organosilicon compound represented by the general formula (1) is preferably added in an amount of 0.01 to 50 parts by mass, more preferably 1 to 30 parts by mass, based on the state after the hydrolysis and condensation reaction, based on 100 parts by mass of the metal particles (solid content). The silane coupling agent represented by any one of the general formulas (2) to (4) and / or the hydrolyzate and / or condensate derived from the partial condensate thereof is added in an amount of 0.01 to 0.8 parts by mass, more preferably 0.01 to 0.7 parts by mass, based on the state after the hydrolysis and condensation reaction, based on 100 parts by mass of the metal particles (solid content).

[0097] Furthermore, whether the first or second method is adopted, it is preferable to thoroughly disperse the metal particles in water, a hydrophilic organic solvent, or a mixed solvent thereof before combining them with the organosilicon compound that is the silicon compound source (or, in the case of forming another coating layer, typically before combining them with the molybdenum compound).

[0098] 3) Other coating layer formation processes As mentioned above, the other coating layer (if any) is preferably formed between the metal particles and the silicon compound-containing layer, and therefore a layer structure of "metal particles / other coating layer / silicon compound-containing layer" can be preferably adopted. The other coating layer is not particularly limited, but may be a molybdenum-containing coating, a phosphate compound coating, or the like. A preferred example of a molybdenum-containing substance constituting the molybdenum-containing coating is the mixed coordination heteropolyanion compound disclosed in JP 2019-151678 A. Examples of components of the other coating layers, including the mixed coordination heteropolyanion compound, are as described above.

[0099] 4) Composite particle recovery process After the step of forming the silicon compound-containing layer (and optionally other coating layers) on the metal particles is completed, the resulting composite particles can be recovered. For recovery, known processes such as washing and solid-liquid separation can be performed as needed. For example, it is preferable to wash the dispersion with an organic solvent and then filter it to remove water and unreacted materials from the cake containing the composite particles. Furthermore, if necessary, the cake containing the composite particles may then be heat-treated, for example, at a temperature in the range of 100 to 500°C. As described below, the composite particles recovered in this manner typically comprise a metal pigment composition containing trace amounts of solvent, including water and hydrophilic solvent, used in the production process.

[0100] 3. Metal pigment composition The metal pigment composition of the present invention obtained as described above can be considered to be a metal pigment composition that contains composite particles including metal particles and one or more coating layers on their surfaces, and also contains solvents such as water / hydrophilic solvents used in the manufacturing process as the remaining solid content (non-volatile content). The metal pigment composition may typically contain 0.02 to 50 parts by mass of a silicon compound that is a hydrolyzate and / or condensate of an organosilicon compound (for example, at least one organosilicon compound represented by the above general formula (1) and at least one silane coupling agent represented by any of the above general formulas (2), (3), and (4), and partial condensates thereof) per 100 parts by mass of metal particles, calculated as the state after the hydrolysis / condensation reaction is completed.

[0101] The metal pigment composition may contain 0.01 to 10 parts by mass of a compound that forms an optional other coating layer (in an optional embodiment in which a molybdenum-containing coating is formed as the other coating layer, a molybdenum-containing compound, for example, a mixed coordination heteropolyanion compound) per 100 parts by mass of the metal particles. The metal pigment composition may have an optional organic oligomer or polymer present in an amount of 0.01 to 50 parts by weight per 100 parts by weight of the metal particles.

[0102] The metal pigment composition may contain at least one member selected from the group consisting of optional inorganic phosphoric acids and their salts, and acidic organic (phosphorous) esters and their salts, in an amount of 0.01 to 20 parts by mass per 100 parts by mass of the metal particles. The metal pigment composition may contain a solvent containing water / hydrophilic solvent used in the manufacturing process as a remainder of the above components (non-volatile content). The amount of the solvent containing water / hydrophilic solvent may be, for example, 0.5 to 95 mass% of the metal pigment composition. Alternatively, the amount of the solvent containing water / hydrophilic solvent may be 1 to 90 mass%, 2 to 80 mass%, or 5 to 70 mass% of the metal pigment composition.

[0103] The metal pigment composition may optionally contain other optional components than those described above, such as at least one of an antioxidant, a light stabilizer, a polymerization inhibitor, and a surfactant.

[0104] As the antioxidant, phenol-based compounds, phosphorus-based compounds, and sulfur-based compounds can be used.

[0105] As the light stabilizer, those used as antioxidants as described above can be used, but representative examples of the light stabilizer include benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylates, oxalic acid derivatives, hindered amine compounds (HALS), and hindered phenol compounds.

[0106] Examples of surfactants include nonionic surfactants such as polyoxyalkylene alkyl ethers, polyoxyalkylene alkylphenyl ethers, oxyalkylene alkylamino ethers, sorbitan fatty acid esters, polyalkylene glycol fatty acid esters, and glycerin fatty acid esters; anionic surfactants such as sulfates, sulfonates, and phosphates; and cationic surfactants such as quaternary ammonium salts. One or more surfactants selected from these can be used. Particularly preferred examples of surfactants include polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, and mixtures thereof.

[0107] The metal pigment composition in the package of the present invention preferably has a pH in the range of 5 to 9. By adjusting the pH in this range, it is possible to further suppress the aggregation of composite particles contained in the metal pigment composition in the package and the progression of color changes. The pH of the metal pigment composition is more preferably in the range of 6 to 8, and even more preferably in the range of 6.5 to 7.5. In order to achieve such a pH of the metal pigment composition, after the process of forming a silicon compound-containing layer (and / or, optionally, other coating layer) on the metal particles is completed, it is desirable to carry out known processes such as washing with a sufficient amount of organic solvent and solid-liquid separation, and repeat these processes to thoroughly wash away and remove polar compounds such as catalysts used in forming the coating layer.

[0108] 4.Packaging container The packaging container of the present invention is used to package a metal pigment composition and is made of thin chrome-plated steel sheet. That is, this packaging container is made by thinly plating a chromium-containing compound onto a base material that is at least partially made of steel plate. If at least a part of the base material of the packaging container (typically substantially the entire base material) is made of steel plate, it has the advantages of being resistant to impact, being less susceptible to leakage and contact with the outside air during transportation, and having a gradual change in internal temperature during storage. Note that the packaging container of the present invention also includes a case in which the main constituent parts such as the base material are made of steel plate, and a part such as the sealing part of the lid (accessories other than the base material and its plating / protective layer, etc.) is made of a resin other than metal.

[0109] The thickness of the substrate is not particularly limited, but may usually be about 500 μm to 50 mm, more typically about 800 μm to 20 mm. The thickness of the substrate is preferably generally uniform throughout, but may be thicker at the top, bottom, or surrounding areas thereof than at other locations.

[0110] Thin chrome-plated steel sheets, also known as tin-free steel, are typically produced by an electrolytic process using an aqueous chromic acid solution. The coating structure may consist of a two-layer coating consisting of a metallic chromium layer on the steel sheet and a hydrated chromium oxide layer. The metallic chromium content of the coating in this form is 50 to 150 mg / m 2 The amount of chromium oxide is 5 to 35 mg / m 2 The total thickness of both films may be about 20 to 50 nm. The thickness of the thin chrome plating film here refers to the average value of thicknesses measured at any five points, including slight variations due to the actual application process. The combination of this packaging container material and the low moisture content of the metal pigment composition makes it possible to suppress the aggregation and color change of the composite particles contained in the metal pigment composition in the package.

[0111] The packaging of the present invention also includes a case in which a protective layer made of resin is further formed on the thin chrome plating at the portion of the packaging container made of thin chrome-plated steel sheet that comes into contact with the metallic pigment composition. The presence of the protective layer made of resin can further suppress the aggregation and color change of the composite particles contained in the metallic pigment composition in the packaging.

[0112] The resin constituting the protective layer is not particularly limited, but examples thereof include resins containing at least one selected from the group consisting of glycidyl ether type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, cyclic oxirane type epoxy resins, novolac phenolic resins, resol type phenolic resins, polyester resins, polyethylene resins, and epoxy resins heat-cured with phenolic resins.

[0113] Epoxy resins include, but are not limited to, glycidyl ether types such as bisphenol A, bisphenol F, hydrogenated bisphenol A, and phenol novolac; glycidyl ester types such as hexahydrophthalic acid glycidyl ester and glycidyl methacrylate copolymer; glycidyl amine types such as tetraglycidyldiaminodiphenylmethane; and cyclic oxirane types such as 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate. These may be used alone or in combination. These epoxy resins are used as coatings by commonly known methods, such as by room-temperature curing through fatty acid modification, by heat curing with a curing agent such as melamine resin or amine, or by forming them into powder coatings or emulsifying them to form cationic electrodeposition coatings.

[0114] The phenolic resin is not particularly limited, but examples thereof include novolac phenolic resin and resol-type phenolic resin. These phenolic resins are used as coating materials by curing with an amine-based curing agent or by heat. These resins may be used alone or in combination of two or more. The resin containing an epoxy resin and a phenolic resin is not particularly limited, but examples thereof include resins obtained by heat curing using a phenolic resin as a curing agent for an epoxy resin. The resin is used as a coating material in its original form.

[0115] The resin more preferably contains an epoxy resin, and more preferably contains a phenol resin. In another preferred embodiment, the resin includes a polyester resin. The polyester resin is not particularly limited, but examples thereof include polyethylene terephthalate resin, polyethylene isophthalate resin, polybutylene terephthalate resin, polytrimethylene terephthalate resin, and copolymerized resins thereof. A typical example is a polyester resin whose main component is a skeleton formed from terephthalic acid and ethylene glycol or 1,4-butanediol. These polyester resins may be used as films laminated onto metals or as powder coatings. These resins may be used alone or in combination.

[0116] The resin layer preferably has a coating thickness of 1 μm to 200 μm. When the resin coating thickness is 1 μm or more, defects in the coating are easily prevented, and the coloring prevention effect tends to be more suitably exhibited. From the viewpoints of cost and productivity, it is preferable that the resin coating thickness is 150 μm or less. The resin coating thickness is more preferably 2 μm to 100 μm, and even more preferably 3 μm to 60 μm. The film thickness here refers to the average value of thicknesses measured at any five points, including slight variations due to the actual application process.

[0117] In the package of the present invention, it is desirable that the packaging container is sealable. If the packaging container is sealable, aggregation of the metallic pigment in the package and progression of color change can be further suppressed. Typically, the package is sealed when storing or transporting the metallic pigment composition for a long period of time, for example, for one hour or more or one day or more.

[0118] The shape of the packaging container of the present invention is not particularly limited, but may be, for example, a generally rectangular prism or a generally cylindrical shape, preferably a generally cylindrical shape. Among generally cylindrical packaging containers, a pail or a drum is preferred. A pail or a drum is a typical container that is convenient for logistics and storage, saves space, and is easy to take in and out of a warehouse, while still allowing the contents to be stably preserved.

[0119] 5. Storage and transportation methods 1)Residue When the package of the present invention is stored in a sealed state in an indoor warehouse at 20°C for one year, the residue of the metal pigment composition after storage is preferably 0.1 wt% or less (based on the total weight of the metal pigment composition at that time). The amount of residue in the present invention was measured by dispersing 50 g of the metal pigment composition removed from the package after storage under the above conditions in 1,000 ml of mineral spirits with a spatula, filtering through a 200-mesh nylon net (manufactured by NBC Corporation), thoroughly washing the residue with acetone, drying at 105°C for 10 minutes, and then measuring the mass, which was used to calculate the percentage of the residue (the method employed in the examples described below). Furthermore, even when the package of the present invention is stored in a sealed state in an indoor warehouse at 20±10°C, preferably 20±20°C, for one year (i.e., even when stored for one year in an indoor warehouse at a constant temperature within this temperature range, or at a temperature that is manually adjusted or naturally fluctuated within this temperature range), the residue of the metal pigment composition after storage is preferably 0.1 wt% or less. By achieving such a residual amount of the metal pigment composition, it becomes easier to obtain a coating material capable of forming a good coating film without lumps. The residual amount of the metal pigment composition is affected by the coating state of the metal particles in the composite particles and the moisture content of the metal pigment composition, so by achieving a coating that meets the above-mentioned specified requirements and a moisture content within the specified range in the package, it becomes easy to control the residual amount to the above-mentioned level. The residual amount is more preferably 0.05% by weight or less, and even more preferably 0.01% by weight or less.

[0120] Furthermore, when the package of the present invention is stored in a sealed state in a heated chamber at 60°C for three months, the residual metal pigment composition after storage is preferably 0.1 wt% or less. Furthermore, when the package of the present invention is stored in a sealed state in a heated chamber at 60°C±10°C for three months (i.e., when stored in a heated chamber at a constant temperature within this temperature range or a temperature manually adjusted within this temperature range), the residual metal pigment composition after storage is preferably 0.1 wt% or less. By maintaining such a residual metal pigment composition level, it becomes easier to obtain a coating material capable of forming a good, blemish-free coating film. The residual metal pigment composition level is affected by factors such as the coating state of the metal particles in the composite particles and the moisture content of the metal pigment composition. Therefore, by achieving a coating that satisfies the above-mentioned requirements and maintaining a moisture content within the specified range in the package, it is easy to control the residual metal pigment composition to the above-mentioned level. The residual metal pigment composition level is more preferably 0.05 wt% or less, and even more preferably 0.01 wt% or less.

[0121] 2) Storage and transportation methods The preservation method of the present invention is a method for preserving a metal pigment composition using the above-mentioned packaging. In the storage method of the present invention, the temperature inside the packaging container during storage of the metal pigment composition is preferably 0 to 50°C, more preferably 10 to 40°C, and even more preferably 15 to 25°C.

[0122] In one embodiment of the storage method, the metal pigment composition is stored for a period of preferably 5 years or less, more preferably 2 years or less, and even more preferably 1 year or less.

[0123] In one embodiment of the preservation method, the warehouse in which the product is stored is preferably one that can be controlled within a range of 0 to 50° C. or 10 to 40° C., and more preferably a constant temperature warehouse that can be controlled within a range of 15 to 25° C. It is preferable that the temperature of the warehouse can be controlled to a constant temperature throughout the entire preservation period.

[0124] The transportation method of the present invention is a method for transporting a metal pigment composition using the above-mentioned package. In one embodiment of the transportation method, the temperature inside the packaging container when transporting the metal pigment composition is preferably 0 to 50°C, more preferably 10 to 40°C, and even more preferably 15 to 25°C.

[0125] In one embodiment of the transportation method, the temperature of the container or cargo space to be transported can preferably be controlled within a range of 0 to 50° C. or 10 to 40° C., and more preferably be a constant temperature container or cargo space that can be controlled within a range of 15 to 25° C. It is preferable that the temperature of the warehouse can be controlled to a constant temperature throughout the entire transportation period.

[0126] In addition, it is desirable to keep the package out of direct sunlight during storage and transportation, as this can increase the possibility of the temperature of parts of the package rising due to direct sunlight. [Example]

[0127] Next, the present invention will be specifically described with reference to examples and comparative examples. The following examples are provided to illustrate the present invention and are not intended to limit the scope of the invention in any way.

[0128] [Reference Example 1] Metallic pigment composition 0.75m diameter, 0.8m diameter, with paddle-type agitator blades of 0.5m diameter 2 To the reaction vessel, 67 kg of commercially available aluminum paste (manufactured by Asahi Kasei Corporation, product name "GX-3100 (average particle size 11 μm, volatile content 74%)") and 230 kg of methoxypropanol (hereinafter abbreviated as "PM") were added, and the mixture was stirred at 100 rpm with a stirring blade, and the dispersion liquid withdrawn from the bottom was circulated externally at a rate of 10 L / min, returning to the reaction vessel from the top, to uniformly disperse the aluminum paste in the PM. Next, phosphotungstomolybdic acid (HPWMoO 40A solution of 0.5 kg of the hydrate in 2.5 kg of methoxypropanol was gradually added, and the slurry was stirred for 1 hour while maintaining the temperature at 40°C. After that, 5 kg of tetraethoxysilane was added as an organosilicon compound, followed by 5 kg of 25% aqueous ammonia and 100 kg of purified water over 3 hours. Then, 0.7 kg of methyltrimethoxysilane was added as a silane coupling agent and stirred for 2 hours. After the reaction was completed, the slurry was cooled and filtered. The filtered slurry was washed five times (i.e., thoroughly) with PM with a moisture content of 200 ppm to reduce the moisture content, and the raw materials and catalysts used in forming the coating layer were thoroughly removed.Then, the slurry was pressure-filtered again to obtain an aluminum pigment composition with a nonvolatile content of 60%.Dry air with a dew point of -40°C was used when handling the slurry, such as during pressure filtration.

[0129] [Reference Example 2] Metallic pigment composition The same procedure as in Reference Example 1 was carried out except that aluminum paste (manufactured by Asahi Kasei Corporation, product name "FD-5090 (average particle size 9 μm, volatile content 7%)") was used, to obtain an aluminum pigment composition with a non-volatile content of 60%.

[0130] [Example 1] A 20-liter thin chrome-plated steel pail (20L pail, manufactured by Shinpo Kogyo Co., Ltd.) was prepared as a packaging container for packaging the metallic pigment composition. 15 kg of the metallic pigment composition prepared in Reference Example 1 was charged into the packaging container and sealed to obtain a package. At this time, the gas phase of the pail was filled with the same dry air (dew point: -40°C) as used in Reference Example.

[0131] [Comparative Example 1] A package was obtained in the same manner as in Example 1, except that an untreated steel pail that had not been thinly chrome plated (corresponding to the structure obtained by removing the thin chrome-plated portion from the thin chrome-plated steel pail used in Example 1) was used as the packaging container for packaging the metal pigment composition.

[0132] [Example 2] A package was obtained in the same manner as in Example 1, except that the metal pigment composition prepared in Reference Example 2 was used.

[0133] Comparative Example 2 A package was obtained in the same manner as in Comparative Example 1, except that the metal pigment composition prepared in Reference Example 2 was used.

[0134] [Example 3] A package was obtained in the same manner as in Example 1, except that PM with a moisture content of 500 ppm was used to wash the filtered slurry.

[0135] [Example 4] A package was obtained in the same manner as in Example 1, except that the number of times the filtered slurry was washed was reduced to one time.

[0136] [Example 5] A package was obtained in the same manner as in Example 1, except that a 20-liter thin chrome-plated steel pail (laminated pail, manufactured by Nippon Tetsukan Co., Ltd.) on which a polyethylene layer with an average thickness of 100 μm was formed was used. Note that the "average thickness" of the polyethylene layer here refers to the average thickness measured at five random locations.

[0137] [Example 6] A package was obtained in the same manner as in Example 1, except that a thin chrome-plated steel pail (manufactured by Shinpo Kogyo Co., Ltd.) was used, on which a layer of epoxy phenolic resin (Daitron #5301, manufactured by Dai Nippon Paint Co., Ltd.) with an average thickness of 7 μm was formed on the part that came into contact with the metal pigment composition. The epoxy phenol resin was applied as a coating agent made by mixing 20% ​​by mass of epoxy resin, 30% by mass of phenol resin, and 50% solvent, and after the solvent was evaporated at room temperature, the resin layer was baked at 210°C for 10 minutes. The "average thickness" of the epoxy phenol resin layer here refers to the average thickness measured at five random locations.

[0138] Comparative Example 3 A package was obtained in the same manner as in Example 5, except that PM with a moisture content of 2000 ppm was used to wash the filtered slurry.

[0139] (Evaluation of Metal Pigment Composition) (Average particle size: D 50 ) The average particle diameter (D 50 ) was measured using a laser diffraction / scattering particle size distribution analyzer (LA-300 / manufactured by Horiba, Ltd.). Isopropanol was used as the measurement solvent. The measurement was carried out according to the instruction manual of the equipment, but it is important to note that the composite particles to be used as samples were subjected to ultrasonic dispersion for 2 minutes as a pretreatment, then placed in the dispersion tank and the measurement was started after confirming that they had been dispersed to the appropriate concentration. 50 was calculated by the instrument software and displayed automatically.

[0140] (Moisture percentage) The moisture content in the metal pigment composition was measured by the Karl Fischer method in accordance with JIS K 0068.

[0141] (pH) The pH of the metal pigment composition was measured at a temperature of 25°C using a glass electrode pH measuring device (PH METER F-15, manufactured by Horiba, Ltd.).

[0142] (Residual percentage of metal pigment composition after storage in package) The packages of metal pigment compositions obtained in each of the above examples / comparative examples were stored for one year in a storage facility at 20±10°C (at a temperature that naturally fluctuated due to the influence of the atmosphere surrounding the storage facility), and then 50g of the metal pigment composition removed from the package was dispersed in 1000ml of mineral spirits with a spatula, filtered through a 200 mesh nylon net (manufactured by NBC Corporation), the residue was thoroughly washed with acetone, dried at 105°C for 10 minutes, and then the mass was measured, and this was used as the mass of the residue to calculate its proportion.

[0143] (Evaluation of coating film obtained from metal pigment composition before and after storage in package) Before storing the packages of the metallic pigment compositions obtained in each of the above examples and comparative examples, and after storing the packages for one year in a storage facility at 20±10°C (a temperature that naturally fluctuates due to the influence of the atmosphere surrounding the storage facility), water-based metallic paints were prepared using the metallic pigment compositions taken out of the packages with the following composition, and the paints and the coating films obtained from them were evaluated using the methods described below. <Composition of water-based metallic paint> Metal pigment composition: 12.0 g as nonvolatile content Methoxypropanol: 18.0g Polyoxyethylene lauryl ether (non-ionic surfactant, Matsumoto Yushi Pharmaceutical Co., Ltd., product name "Marpon L5"): 6.0 g ·Purified water: 12.0g Water-soluble acrylic resin (※1): 110.0g Melamine resin (※2): 18.0g *1: Alumatex WA911, manufactured by Mitsui Chemicals, Inc. *2: Cymel 350, manufactured by Nippon Cytec Industries Co., Ltd. After mixing the above ingredients, the pH was adjusted to 7.7 to 7.8 with dimethylethanolamine, and the viscosity was adjusted to 650 to 750 mPa·s with a carboxylic acid thickener and purified water (B-type viscometer, No. 3 rotor, 60 rpm, 2°C).

[0144] (Coating film evaluation) The water-based metallic paint prepared according to the above formula was air spray painted onto a 12 cm x 6 cm steel plate (manufactured by Miki Coating Co., Ltd.) that had been coated with an undercoat to a dry film thickness of 6 μm, and after pre-drying at 90°C for 10 minutes, an organic solvent-based top coat paint of the following composition was added, dispersed with a spatula for 3 minutes, and then the paint viscosity was adjusted to 20.0 seconds using a Ford Cup No. 4. The paint was air spray painted to a dry film thickness of 20 μm, and dried at 140°C for 30 minutes to prepare a coated plate that was then subjected to the following evaluations. (Composition of organic solvent-based top coat paint) Acrydic 44-179 (DIC, acrylic clear resin) 141g Super Beckamin J-820 (DIC, melamine resin) 35.3g 123.5g toluene

[0145] (paint film particles) The number of bumps on the entire surface of the topcoat film of the resulting coated plate was counted and evaluated according to the following criteria. O: The item could not be seen. △: There were 20 or fewer items. ×: There were more than 20 items.

[0146] (brightness) The resulting painted panels were evaluated using the Alcove LMR-200 laser metallic feel measuring device manufactured by Kansai Paint Co., Ltd. The optical conditions were a laser light source with an incident angle of 45 degrees, and receivers at receiving angles of 0 degrees and -35 degrees. The IV value was measured at a receiving angle of -35 degrees, where the maximum light intensity was obtained from the reflected laser light, excluding the light in the specular reflection area reflected by the coating surface. The IV value is a parameter proportional to the intensity of specularly reflected light from the coating, and indicates the level of light brightness. The obtained IV values ​​were evaluated based on the following criteria. ○: The decrease from the standard (before storage) was less than 40. △: The decrease from the standard (before storage) was 40 or more and less than 60. ×: The decrease from the standard (before storage) was 60 or more.

[0147] (Concealment) The prepared water-based metallic paint was applied to a polyethylene terephthalate sheet (PET sheet) using a 2-mil applicator so that the dry film thickness was 15 μm, and the coating film was dried at 140°C for 30 minutes and visually evaluated. ○: Equal to or slightly lower than the standard (before storage). △: Lower than the standard (before storage). ×: Significantly lower than the standard (before storage).

[0148] (Average thickness of composite particles, average thickness of coating layer) In order to facilitate measurement of particle thickness, etc., the above water-based metallic paint was prepared under the same conditions as those used in the above "Coating Film Evaluation," except that the amount of the metal pigment composition in the paint formulation was reduced to 1 / 10, using a metal pigment composition removed from the packaging before storage. Coated panels were then prepared under the conditions described in the above "Coating Film Evaluation." The coated plate was cut into 1 cm squares using a shearing machine. The cross-section of the obtained coating film was subjected to ion milling using an ion milling device (JEOL Ltd. / IB-09010CP) set up so that the ion beam could be irradiated up to a distance of 20 μm from the cross-section of the coating film, and a precision-polished cross-section sample was prepared by ion milling. The cross section of the resulting coating film (coated plate) was observed with an FE-SEM (Hitachi / S-4700) to evaluate the thickness of the composite particles. The conditions for FE-SEM observation and acquisition were adjusted so that the accelerating voltage was set to 5.0 kV and the image magnification was 10,000 times. Using the image analysis software Win Roof version 5.5 (manufactured by MITANI CORPORATION) from the obtained FE-SEM image (10,000x magnification), the thickness of 100 randomly selected particles on the cross section of the composite particle was measured, and the average thickness was calculated. The thickness uniformity of the composite particle was high, and the difference in thickness depending on the cut part of the particle was small. Therefore, the influence of differences in the cut part of the particle on the average thickness measurement can be ignored.

[0149] The coated plates prepared for the FE-SEM image acquisition were then imaged using a Hitachi S-5500 high-resolution scanning transmission electron microscope (HR-STEM) at 30 kV accelerating voltage and 200,000x magnification to measure the thickness of the composite particle coating. If the coating surface was uneven, the area of ​​the coating was measured using image analysis software WinRoof version 5.5 and divided by the perimeter of the coated particle to determine the coating thickness. For larger particles, it is not necessary to measure the entire area of ​​the coating; instead, measuring the area of ​​a region of approximately 1 μm along the particle surface and dividing this by the particle surface length provides a sufficiently accurate estimate of the coating thickness. Because the coating thickness is generally uniform across particles, the average thickness was calculated for 10 particles.

[0150] [Example 7] The package containing the metal pigment composition obtained in Example 1 was stored for three months in a storage cabinet (heated room) at 60°C (at a substantially constant temperature, including temporary fluctuations within ±10°C), and then the metal pigment composition removed from the package was evaluated in the same manner as in Example 1, except for the storage conditions.

[0151] The evaluation results are shown in Table 1. It was found that the packaging body according to the present invention, which satisfied all of the requirements of items (1) to (4) above obtained in each example, was able to suppress the progression of aggregation and coloration of the metal pigment composition in the packaging body.

[0152] [Table 1] [Industrial Applicability]

[0153] The packaging of the present invention, the metallic pigment composition contained in the packaging after transport and storage by the storage and transport method of the present invention, and coating films obtained using them combine excellent coating film properties such as low VOC content, storage stability when used in aqueous paints, particle suppression, design, and hiding power at a high level that exceeds the limitations of conventional technology. Therefore, these metallic pigment compositions and coating films are suitable for various applications in which metallic pigments have traditionally been used, such as paints, inks, and resin mixing agents, more specifically, for automobile bodies, automobile repair materials, automobile parts, home appliances, plastic parts, PCM paints, highly weather-resistant paints, heat-resistant paints, anti-corrosion paints, ship bottom paints, offset printing inks, gravure printing inks, and screen printing inks. Furthermore, these metallic pigment compositions and coating films are highly applicable in various industrial fields, such as the transportation machinery industry (e.g., automobiles), the electrical and electronics industry (e.g., home appliances), the paint industry, and the printing industry.

Claims

1. A package in which a metal pigment composition containing composite particles having metal particles and one or more coating layers on the surfaces thereof is packed in a packaging container, wherein the metal particles are aluminum or an aluminum alloy, at least one of the coating layers is a silicon compound-containing layer, the pH of the metal pigment composition is in the range of 5 to 9, and the package satisfies the following (1) to (4): (1) The composite particles have a scale-like shape; (2) The composite particles are D on a volume basis when the particle size distribution is measured using a laser diffraction particle size distribution analyzer. ５０ is 1 to 30 μm, (3) The moisture content of the metal pigment composition in the package is 0 to 1000 ppm relative to the mass of the metal pigment composition; and (4) The packaging container is made of thin chrome-plated steel sheet.

2. 2. The package according to claim 1, wherein when the sealed package is stored in an indoor warehouse at 20°C for one year, the residue of the metal pigment composition after storage is 0.1% by weight or less.

3. 2. The package according to claim 1, wherein when the sealed package is stored in a heated room at 60°C for three months, the residue of the metal pigment composition after storage is 0.1% by weight or less.

4. A storage method for storing a metal pigment composition at 0 to 50°C using a packaging body described in any one of claims 1 to 3.

5. A transportation method for transporting a metal pigment composition at 0 to 50°C using a package described in any one of claims 1 to 3.

6. a step of forming a silicon compound-containing layer on the surface of the metal particles by subjecting the organosilicon compound to a hydrolysis / (partial) condensation reaction in a mixed liquid containing metal particles, a silicon-containing raw material containing at least one organosilicon compound, a solvent (water and / or a hydrophilic solvent), and, if necessary, other optional components, thereby obtaining a metal pigment composition containing composite particles having metal particles and one or more coating layers on the surface of the metal particles, the coating layers including the silicon compound-containing layer; a step of adjusting the moisture content of the metal pigment composition containing the composite particles to 0 to 1000 ppm relative to the mass of the metal pigment composition; and a step of packaging the metal pigment composition containing the composite particles in a packaging container so that the pH of the metal pigment composition is in the range of 5 to 9 and the following conditions (1) to (4) are satisfied; A method for packaging a metal pigment composition, comprising: (1) The composite particles have a scale-like shape; (2) The composite particles are D on a volume basis when the particle size distribution is measured using a laser diffraction particle size distribution analyzer. ５０ is 1 to 30 μm, (3) The moisture content of the metal pigment composition in the package is 0 to 1000 ppm relative to the mass of the metal pigment composition; and (4) The packaging container is made of thin chrome-plated steel sheet.

7. 7. The packaging method of claim 6, wherein the metal particles are aluminum or an aluminum alloy.

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